In recent years, advances in technology, as well as ever-evolving tastes in style, have led to substantial changes in the design of automobiles. One of the changes involves the complexity of the electrical systems within automobiles, particularly alternative fuel vehicles, such as hybrid, electric, and fuel cell vehicles. Such alternative fuel vehicles typically use one or more electric motors, perhaps in combination with another actuator, to drive the wheels. Additionally, such automobiles may also include other motors, as well as other high voltage components, to operate the other various systems within the automobile, such as the air conditioner.
Due to the fact that alternative fuel automobiles typically include only a direct current (DC) power supply (e.g., a battery), voltage source (i.e., power) inverters are used to convert the DC power to alternating current (AC) power, which is generally required by the motors. The motors, power inverters, and the battery, as well as other components, are electrically interconnected through a series of conductors, such as cables, referred to as a “DC bus.”
The power inverters convert DC power to AC power primarily by means of switching transistors therein, using for example, Pulse Width Modulation (PWM) techniques. The inverter switching frequencies often approach, and excite, various resonant frequencies in the DC bus, which may result in undesirable noise in the vehicle and high frequency current ripple on the DC bus.
Accordingly, it is desirable to provide a method and system for operating a motor coupled to an electrical bus such that the excitation of resonant frequencies is minimized. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.